Choosing the Right Front Disc Brake Caliper for Your 1987 GMC R1500
Everything you need to know about replacing the single-piston floating calipers on your classic GMC truck.
- The most common failure on an 1987 R1500 is a seized or sticking caliper due to rust; symptoms include pulling, dragging, and a burning smell.
- You MUST verify if your truck has 1.0-inch or 1.25-inch thick rotors before ordering, as the calipers are different for each.
- Always replace calipers in pairs (left and right) to ensure safe, balanced braking performance.
- Coated calipers from brands like Powerstop, Raybestos, or Dynamic Friction offer better rust protection and are a worthwhile investment for longevity.
Is it Time for New Calipers on Your '87 R1500?
The original cast iron calipers on these classic GMC trucks are durable, but they are prone to failure from age and corrosion. The most common problem is a seized or sticking caliper, which happens when the internal piston or the external slide pins rust and can no longer move freely. This can cause serious safety issues. Driving with a faulty caliper is not recommended as it can lead to unpredictable braking or complete failure.
Symptoms of a Failing Brake Caliper
- Pulling to One Side: When you brake, the truck veers left or right. This often means one caliper is stuck and not applying the correct pressure.
- Spongy or Soft Brake Pedal: If the pedal feels mushy or goes closer to the floor, it could be a sign of a fluid leak from a worn caliper seal.
- Brake Fluid Leaks: Puddles of clear or brownish fluid near a front wheel are a definite sign of a leak and require immediate attention.
- Dragging Sensation or Burning Smell: A stuck caliper can keep the pads pressed against the rotor even when you're not braking. This creates a dragging feeling, a strong burning smell, and can cause the wheel to get excessively hot.
- Uneven Pad Wear: If the brake pads on one side of the truck are significantly more worn than the other, a bad caliper is the likely cause.
Important: Check Your Rotor Size
Before ordering, you must know if your R1500 has 1.0-inch or 1.25-inch thick front rotors. The calipers for these two rotor sizes are different and not interchangeable. Measuring your rotor thickness is a critical step to ensure you buy the correct part.
Choosing the Right Aftermarket Caliper Brand
For a vehicle of this age, aftermarket calipers are the standard replacement. Most are remanufactured, meaning an original caliper body (the core) has been cleaned, inspected, and rebuilt with new seals, boots, and often a new piston. Some brands also offer completely new units. Here’s a breakdown of available brands:
| Brand Tier | Brands | Description |
|---|---|---|
| Performance & Coated | Powerstop, Raybestos (Element3), Centric (Posi Quiet) | These brands offer calipers with powder-coated or zinc-plated finishes that provide excellent protection against rust and corrosion. Powerstop is often seen as a performance upgrade and may come in colors like red or black. Coated options from Raybestos and Centric are excellent choices for daily drivers, especially in areas with road salt. |
| Standard Replacement | Cardone, Dynamic Friction, BBB Industries, Raybestos (Professional Grade), Centric (Standard) | These brands are the workhorses of the aftermarket, offering reliable, OE-quality replacements. Cardone and Raybestos are long-standing names in the brake industry, though opinions on quality can be mixed, as with any remanufactured part. Dynamic Friction is known for offering new calipers with a protective zinc coating. BBB Industries provides dependable remanufactured calipers that meet factory specifications. |
Pro Tip: Always replace calipers in pairs (both front left and right) to ensure balanced and safe braking. Replacing only one can cause the truck to pull to one side.
Known Issues, Recalls, and Service Bulletins
Searches of the National Highway Traffic Safety Administration (NHTSA) database did not find any specific recalls or technical service bulletins (TSBs) related to the brake calipers for the 1987 GMC R1500. Any recalls found for GMC trucks relate to much newer models and different braking system components. The most common problems reported by owners in forums are age-related failures like sticking pistons and seized slide pins due to corrosion.
Frequently Asked Questions
What is a "core charge"?
Since most calipers are remanufactured, a core charge is a deposit you pay when you buy the part. You get this deposit back when you return your old, worn-out caliper. This ensures a steady supply of old parts to be rebuilt.
What's the difference between a "loaded" and "unloaded" caliper?
A "loaded" caliper comes complete with new brake pads and all the necessary mounting hardware. An "unloaded" or "semi-loaded" caliper includes the caliper and bracket but does not include brake pads, allowing you to choose your preferred pads separately.
Can I rebuild my own calipers?
Yes, rebuild kits with new seals and boots are available. This can be a cost-effective option if the caliper casting and piston are in good, corrosion-free condition. However, for most DIY mechanics, replacing the entire caliper with a quality remanufactured unit is faster and more reliable.
Do I need special tools to replace my calipers?
You will need standard mechanic's tools, a torque wrench, a C-clamp to compress the piston (if installing pads), and tools for bleeding the brakes. Properly bleeding the brakes after installation is a critical step to remove all air from the hydraulic lines.
Technical Specifications
The 1987 GMC R1500 uses a cast iron, single-piston, floating front disc brake caliper. It is available in two different configurations to fit either 1.0-inch or 1.25-inch thick brake rotors.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- GMC R1500: